GB1590190A - Heat-developable sensitive silver salt photographic material - Google Patents

Description

PATENT SPECIFICATION ( 11) 1590190

O ( 21) Application No 53525/77 ( 22) Filed 22 Dec 1977 0 ( 31) Convention Application No 753 236 ( 19)( 19 ( 32) Filed 22 Dec 1976 in o ( 33) United States of America (US) < ( 44) Complete Specification published 28 May 1981 _ ( 51) INT CL 3 GO 3 C 1/06 ( 52) Index at acceptance G 2 C 217 223 25 X 27 Y 301 306 316 321 331 333 340 341 39 Y C 19 E 2 B C 19 Y ( 72) Inventor PAUL BARRETT MERKEL ( 54) HEAT-DEVELOPABLE SENSITIVE SILVER SALT PHOTOGRAPHIC MATERIAL ( 71) We, EASTMAN KODAK COMPANY, a Company organized under the Laws of the State of New Jersey, United States of America of 343 State Street, Rochester, New York 14650, United States of America do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following 5 statement: -

This invention relates to a heat-developable sensitive silver salt photographic material.

Photographic materials are known wherein a latent image formed by exposure to light can be developed to a visible image by heating the material uniformly Such 10 materials may contain, for example, photosensitive silver halide, a silver halide developing agent, a developing agent activator precursor and an image stabilizer precursor.

When such a material is heated the developer activator and the image stabilizer are released from their respective precursors and development of the latent image and stabilization of silver halide occur simultaneously, the two reactions competing It 15 is possible for a single compound to be a precursor of both a development activator and an image stabilizer, and certain of the compounds with which the present invention is concerned are of this kind.

According to the present invention there is provided a heat-developable sensitive photographic material which comprises a support and in a layer or layers coated 20 on one side thereof (a) a photographic silver salt, (b) a developing agent for the silver salt (a), or a precursor of such a developing agent, (c) a binder, and (d) a precursor of an activator for development of the silver salt (a), this precursor being a neutral compound comprising a cationic base portion and an anionic acid portion which is a 2-carboxycarboxamide 25 A precursor of the developing agent releases the developing agent when the photographic material is heated.

The 2-carboxycarboxamide compounds (d) have low toxicity and do not seriously affect the sensitometric and keeping properties They do not, on heating, have any marked tendency to produce bubbles or lower density areas visible through a 10 x 30 magnifying glass termed 'pinholes', either of which defects are undesirable in photographic materials designed for microimaging.

The compounds (d) can be prepared by processes known in the art lsee, for instance, J Chem Soc, 127 1791 ( 1925)1 The preparation of N,N'ethylenebis (phthalamic acid) is an example of preparation of the 2carboxycarboxamide moiety 35 as described According to this preparation, 7 0 grams of ethylenediamine dissolved in ml of 3 A alcohol (a 95/5 by volume mixture of ethanol and methanol) is poured into a solution of 40 0 grams (that is a 15 % excess) of phthalic anhydride in 300 ml of acetonitrile plus 100 ml os 3 A alcohol with vigorous stirring A white solid forms initially which soons dissolves followed by formation of a white precipitate The 40 covered solution is stirred for 1 hour at ambient temperature (about 20 WC) and pressure The resulting product (NN'-ethylenebis(phthalamic acid) (Compound C) is filtered, washed with ether and dried Thlis product is essentially water insoluble but is soluble in methanol or an aqueous base solution It decomposes between about 155 and 195 WC with evolution of water It can be mixed with a chosen base portion 45 to provide a compound (d) for use in a heat-processable photographic material accord2 1,590,1902 ing to the invention This mixing of the acid and base portions can be carried out in situ, i e in the presence of other components of the heat processable photographic material, for instance the developing agent and binder Alternatively, the acid and base portions can be mixed separately in order to provide increased control of the preparation The mixing can be carried out under ambient conditions of temperature 5 and pressure such as at about 20 'C and atmospheric pressure Mixing of the acid and base portions is usually carried out at stoichiometric ratios, however, concentrations outside these ratios can be useful in order to ensure reaction completion.

The desired product can be purified by means known in the art; however, the impure product containing free phthalamic acid and the free base moiety can also be useful 10 The preferred activator precursor compounds including activatorstabilizer precursor compounds) (d), are represented by the formula:

0 O NHR NHR e 0 00 wherein B is a protonated basic nitrogen-containing moiety; each of Y and Z is a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms, which may be 15 substituted, or Y and Z together represent the atoms which complete a ring structure, preferably a carbocyclic ring structure, such as a phenylene group, a cyclohexane group or a norbornane group which ring structure may be substituted R is a hydrogen atom or an alkyl group containing 1 to 10 carbon atoms, which may be substituted, such as a methyl, ethyl, propyl, butyl or hexyl group, or a carbokamido group, 20 especially 0 O o or 00 or O 0 O wherein n' is 1 to 6; N is an integer (usually 1 or 2) such that the compound is neutral, i e has a net charge of zero.

Suitable substituent groups which may be present in R and Y and/or Z are, 25 for example, hydroxyl, carboxamido and carbamoyl.

Especially useful compounds of Formula I (a) or (b) are those wherein B is an amine or isothiuronium moiety, particularly such a moiety having a p Ka value within the range of 8 to 12 and wherein the 2-carboxycarboxamide undergoes less than 10 % weight loss, except loss due to water release, in a thermogravimetric scan 30 between 30 'C and about 180 WC where the scan rate is about 400 C per minute A detailed description of thermogravimetric analysis can be found in Instrumental

Methods of Analysis by Willard, Merritt and Dean, Vanostrand, 1965, Chapter 17.

Such a test can demonstrate the desired degree of lack of volatility of the byproducts of the precursors in the photographic material of the invention The analysis, as 35 described, involves the weight loss measurement of a sample as a function of temperature at a given rate of temperature increase.

The exact mechanism by which the activator precursor functions within a heat processable photographic material according to the invention is not known with certainty However it is believed that, upon heating, the precursor undergoes a ther 40 mal cyclization of the acid portion of the precursor producing an imide and also liberates a base or base stabiliser moiety This is illustrated, for example, in the following equation:

1,590,190 1,590,190 3 0 0 Nf 4 CH 2 o ( ( H 2 i B A Q NCH 2 0 0 + 2 H 20 + B B can be any of a variety of protonated nitrogen containing moieties that do not significantly adversely affect the desired properties, such as sensitometric properties, of the described photographic materials Preferred base moieties are amine and isothiuronium moieties which have a p Ka value within the range of 8 to 14, typically 5 8 to 12 Especially useful amine or isothiuronium moieties are those represented by the formula:

R 1-N S C 12)m R 3 (II) R 2 N H m 1 wherein m is 2 to 6; m' is 1 or 2; each of R' and R 2 is hydrogen, or an alkyl group, preferably containing 1 to 5 carbon atoms, or R' and R 2 together are the atoms 10 necessary to complete a five or six-member heterocyclic nucleus, such as e C > and N H H Ra is a group that reduces volatility of the described precursor, especially a group that is 0 O Il Il CH 3 CNH or CH,3 NHCNH 15 when m' is 1; or, when m' is 2, is 0 I -NHCNH, 02 S< or CH 35 O 2 N<; and especially useful amine moieties such as N Hp wherein p is 1 or 2; R', when p is 1, is hydrogen or alkyl, especially alkyl containing 20 1 to 3 carbon atoms and when p is 2, is alkylene, especially alkylene containing 1 to 6 carbon atoms In the case of a precursor containing a moiety of Formula II or III as described, the precursor is both an activator precursor and a stabilizer precursor.

In certain cases it is not necessary to have the base portion of the precursor as described be a stabilizer precursor as well as an activator precursor In those in 25 stances, an activator precursor having a p Ka within the range of 8 to 12 in which the anionic acid portion is of Formula I(a) or I(b) and the cationic portion is of the formula:

1,590,190 R R 1 R 5 (CH 2-)-N( \ (IV) 013 R 7 r wherein q is 1 to 6; r is 1 or 2; each of R 6 and R' is hydrogen or an alkyl group which preferably contains 1 to 4 carbon atoms; R 5, when r is 2, is -NHCNH-, CHSO 2 N<, Li 0 0 NI.QNH-ECH 2)s CNH-, or NHCNHK WNHCNH-; s is 1 to 6; RW, when r is 1, may be H N / NThe described activator precursor containing the 2-carboxy-carboxamide moiety should undergo less than 10 % weight loss, except loss due to water release, in a thermogravimetric scan between the 30 'C and about 1800 C where the scan rate 10 is about 40 WC per minute, as described.

Selection of an optimum activator precursor, especially an activatorstabilizer precursor, or combination of compounds, as described, should be carried out with regard to a variety of factors, including the particular image desired, the processing conditions, the particular photographic silver salt and other components of the 15 photographic material chosen, and the degree of desired image stability One selection test, for example, is described in following Example 1 Thus the compound to be tested can be incorporated in the material of Example 1 instead of the 2carboxycarboxamide compound of that example If the test results obtained are similar to those for the Example 1 compound, the compound tested is considered satisfactory 20 That is, in the case of an activator precursor, the compound is considered satisfactory if an image is developed having about the same maximum and minimum densities as the image developed according to Example 1 In the case of an activatorstabilizer precursor, the compound is considered satisfactory if an image is developed and the maximum density of that image is similar to or greater than that of the image 25 developed according to Example 1.

An especially useful heat developable photographic material according to the invention is one wherein the activator precursor is an activatorstabilizer precursor containing an N,N'-ethylenebis(phthalamic acid) moiety.

An especially useful activator-stabilizer precursor, as described, is 1,3bis( 2 30 amino-2-thiazolinyl)propane NN'-ethylenebis(phthalamic acid) this comprising Compounds A and C.

Combinations of activator precursors, especially combinations of activatorstabilizer precursors, as described, can be useful according to the invention, if desired.

Some of the activator precursor compounds, typically activator-stabilizer pre 35 cursor compounds, have limited solubility in aqueous formulations and may require some added solvents in the preparation of photographic compositions.

The photographic materials, as described, contain a photographic silver salt, preferably photosensitive silver halide due to its high degree of photosensitivity Other useful photographic silver salts include, for example, certain silver triazoles and silver 40 aminotriazoles Useful photographic silver halides are disclosed in Product Licensing Index, Vol 92, Dec 1971, Item 9232, Section 1.

The activator-stabilizer precursors used for the invention are particularly useful with silver bromide and silver bromoiodide materials A range of concentration of photographic silver salt can be useful in the photographic materials of the invention 45 Typically, a concentration of photographic silver salt, especially photographic silver halide, is used that, when coated on a support, provides a photographic element 1,590,190 containing about 1 to about 30 mg of silver per square decimeter.

A silver salt developing agent, typically a silver halide developing agent, is useful in the photographic materials and processes as described to provide a developed image Useful silver salt developing agents are described in Section VI of the aboveidentified Product Licensing Index Item 5 A range of concentration of photographic silver salt developing agent (or precursor thereof) can be useful in the described materials according to the invention.

Typically, a concentration within the range of 0 1 to 2 0 moles of developing agent per mole of silver in the photographic material is employed, preferred values being in the range 0 5 to 1 0 mole of developing agent per mole of silver 10 In a photographic material of the invention a useful concentration of activator 10 precursor is from 02 to 4 0 moles and preferably 0 5 to 2 0 moles, per mole of total silver The photographic silver salt, preferably photographic silver halide, is typically present at a coverage of 0 02 to 0 3, and preferably 0 05 to 0 2, millimole per square decimeter of support.

An especially useful embodiment of the invention is a heat developable and heat 15 stabilizable photographic material comprising a support having thereon, coated on one side with a layer or layers containing (a) photographic silver halide, (b) a 3pyrazolidone silver halide developing agent, (c) a polymeric binder, typically a gelatino binder, and (d) an activating and stabilizing concentration of an activator-stabilizer 20 precursor represented by the formula:

0 O LNHCH 2 CH 2 NH _() E O O 22 0 0 0 0 H Another preferred embodiment is a heat developable and heat stabilizable photographic material comprising a support coated on one side with a layer or layers containing (a) a photographic silver halide, especially a photographic silver bromo 25 iodide, (b) an activating and stabilizing concentration of the activatorstabilizer precursor comprising Compounds A and C, namely 1,3-bis( 2-amino-2thiazolinyl)propane N,N'-ethylenebis(phthalamic acid), (c) as an auxiliary stabilizer precursor 1,3-bisl 25(N,N'-ethyleneisothiourea)ethyllurea (Compound (D), (d) N,Nethylenebis(phthalamic acid) (Compound C), (e) the silver halide developing agent 4hydroxymethyl-4-methyl 30 1-phenyl-3-pyrazolidone, and (f) a gelatino binder.

Another especially useful embodiment of the invention is a heat developable and heat stabilizable photographic material comprising a support coated on one side with a layer or layers containing (a) photographic silver bromoiodide, (b) the development restrainer 1-methyl-3-l 2-(methylcarbamoylthio) ethyll urea represented by the 35 formula:

0 O II II C Ha NHCSCH 2 CH 2 NHCNHCH,, (c) a toning concentration of the image toner represented by the formula:

NH H ((Q N"CH 2 CH 2 NH As) ' CH 25 o 02 CH 2 z COP)2 N > _ N H H H 20 1,590,190 (CH 2 SO 2 CH 2 COOE)2 H 20 (e) an activating and stabilizing concentration of the activatorstabilizer precursor comprising Compounds C and D 1,3-bisl 2 S-(N,N'-ethyleneisothiuronium ethyll urea-N, N-ethylenebis (phthalamic acid) represented by the formula:

o O NHCU 2 CH 2 NH (DdE) Go, 0 ee o O N'J ( ( >-SCH 2 CH 2 N Hi C-0 H (f) a first silver halide developing agent which is 2-(n-propyl)-4,5,6trihydropyrirnidine, (g) a second silver halide developing agent which is 4-hydroxymcthyl-4methyl-1phenyl-3-pyrazolidone (referred to herein as R-1), and (h) a polymeric binder, especially a gelatino binder 10 As described, it is often useful to include an auxiliary stabilizer precursor in a photographic material of the invention Useful auxiliary stabilizer precursor compounds include, for example, those described in 'Research Disclosure', November

1976, Item 15109 and described and claimed in U K Patent Application 32794/77 (Serial No 1,579,260) These compounds include activator stabilizer precursors 15 having an acid portion which is an alpha-sulphonylacetate Especially useful auxiliary activator-stabilizer precursor compounds are those having a base portion which is a protonated basic nitrogen containing moiety and an acid portion that is an alphasulphonylacetate Particularly useful alpha-sulphonylacetate compounds include thos wherein the alpha-sulphonylacetate moiety is an ethylenebis (sulphonylacetate), methyl 20 enebis(sulphonylacetate) or phenylsulphonylacetate An especially useful auxiliary activator stabilizer precursor is 1,3-bisl 2 S-(N,N'-ethyleneisothiourea) ethyllurea, ethylenebis(sulphonylacetate) (this compound can also be named as R,/P'ureylenebis( 2-ethylthio-2-imidazolinium)ethylenebis(sulphonylacetate) A range of concentration of auxiliary activator-stabilizer precursor can be useful in the described photographic 25 materials according to the invention A useful concentration of auxiliary activatorstabilizer precursor is typically within the range of 0 1 to 1 0 mole per mole of silver in the described photographic material Mixtures of auxiliary activator-stabilizer precursors can be useful if desired.

It is useful in some instances to include a development restrainer in the photo 30 graphic materials according to the invention in order to provide improved image discrimination A development restrainer, is a compound which reduces development on fog centers producing lower Dmin values Useful development restrainers include, for example, 1-methyl-3-l 2-(methylcarbamoylthio)ethyllurea and bromide ion.

Typically, the concentration of development restrainer is from 0 01 to 0 2 mole per 35 mole of silver in the photographic material.

A photographic material of the invention can be prepared by coating the necessary constituents on a support Any of the coating methods and means known in the photographic art can be used and if photographic material contains two or more layers these layers can be coated simultaneously 40 Silver halide used as the silver salt (a) can be washed or unwashed to remove soluble salts; can be chemically sensitized; can contain development modifiers that function as speed-increasing compounds; and can contain antifoggants and emulsion stabilizers, as described in the above-mentioned Product Licensing Index Item.

The photographic materials of the invention can contain hardeners, antistatic 45 layers, plasticizers, lubricants, coating aids, matting agents, brighteners, and absorbing and filter dyes which do not adversely affect the properties of the heat developable materials of the invention These addenda are described, for example, in the abovementioned Product Licensing Index publication.

The heat developable photographic materials, as described, can contain a variety 50 1,590,190 A 7 1,590,1907 of vehicles and binders, alone or in combination The photographic material typically contains a polymeric binder.

A photographic material, according to the invention, may comprise an overcoat layer, interlayer or subbing layer Useful natural and synthetic polymers include those described in the above Product Licensing Index publication Especially effective poly 5 meric binders are those which can withstand processing temperatures above about 2500 C.

The photographic and other layers of a photographic material of the invention can be coated on a variety of supports It is necessary that the support be able to withstand the processing temperatures to be used which may be as high as 250 'C 10 or more Useful supports include, for example, cellulose ester films poly(vinyl acetal) film, poly(ethylene terephthalate) film, polycarbonate film, glass, paper and metal.

Typically a flexible support is employed, especially a paper support.

The photographic materials of the invention can contain spectral sensitizing dyes to confer additional sensitivity to the light-sensitive slver salts, especially light 15 sensitive silver halide Useful spectral sensitizing dyes are described, for example, in the above noted Product Licensing Index publication Combinations of spectral sensitizing dyes can be useful if desired In addition, supersensitizing addenda which do not absorb visible light can be useful in the described materials.

The spectral sensitizing dyes and other addenda useful in photographic materials 20 according to the invention can be incorporated into these materials from aqueous compositions, such as water solutions, or suitable organic solvent compositions, such as organic solvent solutions The sensitizing dyes and other addenda can be added using a variety of procedures known in the photographic art, such as described in the above Product Licensing Index publication 25 The activator precursors and activator-stabilizer precursors used for the invention can be incorporated in one or more layers of a photographic material of the invention such as in the silver salt containing layer and/or an overcoat layer and/or a layer between the silver salt-containing layer and the support It is of course necessary for the layer or layers to be such that the necessary imageforming, and 30 any other, reaction can take place when the material is heated to the processing temperature.

A variety of saccharides can be useful in combination with the described 2carboxycarboxamide compounds as they may provide a more fluid processing melt.

Useful saccharides are described, for example, in United Kingdom Patent 930,572 35 A concentration of 0 01 to 20 moles of saccharide per mole of the described 2-carboxycarboxamide compound is typically useful.

Because the described 2-carboxycarboxamide activator-stabilizer precursors are useful as activator precursors for developing agents and as stabilizer precursors, no other stabilizers or stabilizer precursors are needed in the described materials of the 40 invention However, other stabilizers or stabilizer precursors can be useful with the photographic materials and process of the invention, if desired For example, certain stabilizer precursors which form a stable silver complex upon heating in the described materials can be useful in combination with the 2carboxycarboxamides described herein Examples of such other stabilizer precursors are certain isothiuronium 45 compounds such as described in U S Patent 3,669,670 and United Kingdom Patent 1,374,806 Halogen containing stabilizer precursors, such as tetrabromobutane or 2tribromomethylsulphonylbenzothiazole, can also be useful in combination with the described 2-carboxycarboxamide compounds.

After imagewise exposure of a photographic material according to the invention 50 to provide a developable image this image can be developed by heating the material to a temperature within the approximate range of 120 to 200 C (usually within the range of 150 to 1800 C) until the desired image is developed, In the case of a photographic material containing an activator-stabilizer precursor, such heating also brings about stabilization The time of heating necessary is usually in the range 1 to 55 seconds, and often no more than 30 seconds By increasing or decreasing the temperature a shorter or longer processing time can be achieved.

A variety of imagewise exposure means and energy sources can be useful for providing a latent image in the photographic material The exposure means can be, for example a light source, a laser, an electron beam or an X-ray source Various 60 means are useful for providing the necessary heating; for instance a hot plate, heated iron, heated rollers or dielectric heating means.

Small concentrations of moisture, for instance, the concentrations which are present in conventional photographic paper supports at normal temperatures and humidities, and the water that is released upon heating the 2carboxycarboxamide 65 1,590,190 compound, are believed to be helpful during the heat-processing of a material of the invention.

While it is not necessary, an additional activator precursor, can 'be used with the described 2-carboxycarboxamide compound Useful development activators or activator precursors are described, for example, in Belgian Patent 709, 967 Examples 5 of useful activator precursors include guanidinium compounds, such as guanidinium trichloroacetate, diguanidinium glutarate, succinate or malonate; quaternary ammonium malonates such as piperizinium or piperidinium malonate; amino acids; such as 6aminocaproic acid and glycine Other activator precursors are described, for example, in United Kingdom Patent 998,949 10 The following examples are included for a further understanding of the invention.

Example 1.

Use of 1,3-bis( 2-amino-2-thiazolinyl)propane N,N-ethylenebis(phthalamic acid) in a heat developable photographic material according to the invention.

The following composition was mixed and then coated from water on a 4 mil, 15 gel subbed, poly(ethylene terephthalate) film support:

gelatin 27 0 mg/din 2 ( 250 mg/ft 2) Surfactant (Surfactant 10 G which is a nonylphenoxypolyglycidol 1 1 mg/din M 2 20 _ -available from Olin Corp, U S A) ( 10 mg/ft 2) 4-hydroxymethyl-4-methyl-1-phenyl 14 0 mg/din 2 3-pyrazolidone (developing agent R-1) ( 130 mg/ft 2) N,N'-ethylenebis(phthalamic acid) 22 7 mg/dm 2 (referred to herein as Compound C) ( 210 mg/ft 2) 25 1,3-bis lZS-(N,N'-ethyleneisothiourea) 16 2 mg/dm 2 ethyllurea (referred to herein as ( 150 mg/ft 2) Compound D) 1,3-bis( 2-amino-2-thiazolinyl)propane 42 6 mg/dm 2 N,N'-ethylenebis(phthalamic acid) ( 395 mg/ft 2) 30 2 C Ha OH photographic silver bromoiodide 14 O mg Agfdm 2 (unsensitized silver bromoiodide ( 130 mg Ag/ft 2) having an average grain size of 0 12 microns) 35 The resulting coating was permitted to dry at 43 C to provide a heat developable photographic material according to the invention (The p H of the composition prior to coating was adjusted to 4 5 with one normal nitric acid) The heat developable photographic material was overcoated with 50 mg/ft 2 ( 5 4 mg/din 2) of polymethylmethacrylate (available as 'Elvacite' 2009 which is a trade mark of E I Du Pont Demours Co, 40 U.S A) The polymethylmethacrylate was coated from dichloromethane to provide increased resistance to abrasion and other markings upon processing The heat developable photographic material was then sensitometrically exposed to white light to provide a developable latent image, and developed by contacting the material with a metal block for 25 seconds at 160 C A developed image was produced having a 45 purple tone The developed image was light stable and had a maximum diffuse density of 1 7 and a minimum diffuse density of 0 1.

The above procedure was repeated with the exception that prior to imagewise exposure, the photographic material was incubated for 2 weeks at 38 C and 50 % so 50 relative humidity The photographic material after imagewise exposure and processing 50 provided a developed image having a maximum diffuse density of 1 6 and a minimum diffuse density of 0 1 The developed images in each case were free of "pinholes".

Example 2.

Use of higher speed photographic silver halide.

The following composition was mixed and then coated from water on a poly 55 1,590,190 (ethylene terephthalate) film support and after drying was overcoated with 50 mg/ft 2 ( 5.4 mg/din M 2) of polymethylmethacrylate:

gelatin 27 0 mg/dm 2 ( 250 mng/ft 2) Surfactant l OG 1 1 mg/din 2 5 ( 10 mg/ft 2) R-I (developing agent) 14 0 mg/din M 2 ' ( 130 mg/ft 2) Compound C 45 9 mg/dm 2 ( 425 mg/ft 2) 10 Compound D 20 5 mg/dm 2 ( 190 mng/ft 2) Compound F represented by the 19 4 mg/dm 2 formula: ( 180 mg/ft 2) CH 3 0 II 11 (CH 3 N-CH 2 CH 2 CH 2-NH-C-NH-CH 2 CH 2 CH 2 15 (C CI silver bromoiodide emulsion 14 0 mg Ag/dm 2 chemically sensitized with ( 130 mg Ag/ft') sulfur and gold (silver bromoiodide gelatino emulsion having an average grain size of 0 1 20 microns) The p H of the resulting composition was adjusted to 4 5 with one normal nitric acid.

The resulting photographic material was imagewise exposed, as described in Example 1, to provide a developable latent image It was then heated for 30 seconds 25 at 160 C to provide a developed image A similar photographic material, that wasimagewise exposed in the same manner and then heated for 10 seconds at 180 C, also provided a developed image The devloped image in each instance had a diffuse maximum density of 1 7 and a diffuse minimum density of 0 1.

The procedure was repeated with the imagewise exposure being provided with 30 a blue light to determine the minimum energy level required to produce a density of 1 0 in the developed image It was found that a blue light energy of only 4 ergs/ cm 2 was required to produce such a density.

The procedure was repeated with the exception that the photographic material was incubated for 1 week at 38 C and 50 % relative humidity prior to the described 35 imagewise exposure The resulting developed image had a maximum density of 1 7 and a minimum density of 0 15 The photographic speed of the material remained essentially unchanged Specular maximum density of the resulting developed material was 1 9 with a specular minimum density of 0 18.

Example 3 40

Use of another 2-carboxycarboxamide compound.

The composition described below was mixed and then coated from water onto a poly(ethylene terephthalate) film support, permitted to dry at 43 C, and then overcoated with 50 mg/ft 2 ( 5 4 mg/dm 2) of polymethylmethacrylate as described in Example 1: 45 gelatin 21 6 mg/dm 2 ( 200 mg/ft 2) Surfactant l OG 1 1 mg/dm 2 ( 10 ming/ft 2) 1,590,190 a in 1 590190 1 R-1 (developing agent) N,N'-hexamethylenebis(succinamic acid) (Compound B) Compound D 1,4-bis( 2-amino-2-thiazolinyl) butane N Nt'-examethylnebis (succinamic acid) from Compounds E and B, represented by the formula:

14.0 mg/din' ( 130 mg/ft 2) 27.0 mg/dinm 2 ( 250 mg/ft 2) 24.8 mg/dm 2 ( 230 mg/ftr) 22.2 mg/dn ( 205 mg/ft') K No CHCH 2 > photographic silver bromoiodide (described in Example 1) 14.0 mg Ag/dm 2 ( 130 mg Ag/ft') The resulting photographic material was imagewise exposed to light to provide a developable latent image The resulting image was developed by heating the material at 160 C for 20 seconds A developed image was provided having a diffuse maximum density of 1 7 and a diffuse minimum density of 0 06.

Example 4.

Use of a combination of a 2-carboxycarboxamide compound with a different asulphonylacetic acid compound.

The following composition was mixed and then coated from water onto a polyethylene coated paper support containing a layer of poly(acrylamide-co-lvinylimidazole) (weight ratio 90:10) on the polyethylene:

gelatin Surfactant l OG R-1 (developing agent) 2-(n-propyl)-4,5,6-trihydroxypyrimidine (auxiliary developing agent) Compound C Compound D a-sulphonylacetate compound represented by the formula:

21.6 mg/dinm 2 ( 200 mg/ft) 1.1 mg/din M 2 ( 10 mg/ft 2) 2.2 mg/din 2 ( 20 mg/ft 2) 5.4 mg/dinm 2 ( 50 mg/ft 2) 17.3 mg/dm 2 ( 160 mg/ft 2) 12.4 mg/dinm 2 ( 150 mg/ft') 24.3 mg/dm 2 ( 225 mg/ft 2) 1,590,190 11 1 A 590,190 11 H S N NHCH 2 CH 2 NH C( 2502 CH 2 C 02 2 H 20 image toner represented by the 0 1 mg/dm 2 formula: ( 1 mg/ft 2) & 5 NH $ N/ H where F is phenyl development restrainer represented 0 2 mg/dinm 2 by the formula: ( 2 mg/ft 2) O O II II CH 3 NH-C-SCHCH 2 NH-C-NHCH 3 photographic silver bromoiodide 8 6 mg Ag/dm 2 10 (unsensitized silver bromoiodide ( 80 mg Ag/ft 2) having an average grain size of 0.09 microns) The p H of the composition was adjusted prior to coating to 4 5 with one normal nitric acid The resulting photographic material was overcoated with 50 mg/ft 2 15 ( 5.4 mg/dm 2) of polymethylmethacrylate as described in Example 1.

The photographic material was imagewise exposed to light to provide a developable latent image and then heated for 30 seconds at 160 to provide a developed image The procedure was repeated with the exception that the photographic material after imagewise exposure was heated for 10 seconds at 180 C In each instance the 20 developed image was nearly neutral (black) and was light stable The maximum reflection density of the developed image was 1 4 and the minimum reflection density was 0 1 The photographic material after processing was free from "pinholes" even at a processing temperature of 180 C.

Example 5 25

The procedure described in Example 1 was repeated with the exception that the 2-carboxycarboxamide represented by the formula: (Compound G); 0 o X:;N CH 2-NH X O oo o was used in place of the 2-carboxycarboxamide (Compound C) of Example 1.

The resulting developed image had a maximum density of 1 4 and a minimum 30 density of 0 08 upon heating the imagewise exposed material for 30 seconds at C.

Example 6.

A procedure similar to that described in Example 5 was repeated with the exception that the following 2-carboxycarboxamide compound (Compound H) was 35 used instead of Compound G.

1,590,190 12 1,590,190 12 o O 0 NNH-CH 2 t N Oc$ 00 :0-gc 0 o O A developed image was produced.

Example 7.

A procedure similar to that described in Example 5 was repeated with the exception that the 2-carboxycarboxamide compound was replaced with compound i: 5 0 o O N 1-CH 2 o0 O The photographic material according to this example contained a stabilizer precursor (Compound A) represented by the formula:

( @>Es NOCH 2)CH 2 H The photographic material was imagewise exposed to provide a developable 10 latent image as described in Example 1 The resulting image was developed by heating the material for 20 seconds at 160 C This provided a developed light-stable image.

Example 8.

A procedure similar to that described in Example S was repeated in which the I following 2-carboxycarboxamide compound (Compound K) was used, instead of Compound G, with Compound A to provide the neutral compound.

0 O The above 2-carboxycarboxamide compound was incorporated in the photographic layer as an aminothiazoline derivative The resulting photographic material 20 was imagewise exposed and processed as described in Example 1 to provide a developed image having a maximum density of 0 8 and a minimum density of 0 04.

Example 9.

The procedure described in Example 5 was repeated with the exception that the following 2-carboxycarboxamide compound (Compound L) was used instead of 25 Compound G:

0 o 0 O 1,590,190 1,590,190 13 The photographic material according to this example contained a combination of stabilizers consisting of Compounds D and F The photographic material was imagewise exposed to provide the developable latent image as described in Example 1, then heated for 30 seconds 4 t 160 C The resulting developed image had a maximum density of 2 0 and a minifimum density of 0 12 (the composition contained about 5 mg Ag/dm 2).

Claims (14)

WHAT WE CLAIM IS: -

1 A heat-developable sensitive photographic material which comprises a support and in a layer or layers coated on one side thereof (a) a photographic silver salt, (b) a developing agent for the silver salt (a), or a precursor of such a developing agent, to 10 (c) a binder, and (d) a precursor of an activator for development of the silver salt (a), this precursor being a neutral compound comprising a cationic base portion and an anionic acid portion which is a 2-carboxycarboxamide.

2 A material according to claim 1 wherein the anionic portion of the precursor (d) is of the formula: S 15 o O or 0 e 00 o O wherein each of Y and Z is a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms, which group may be substituted, or Y and Z together complete a carbocyclic ring, and R is a hydron atom, an alkyl group containing 1 to 10 carbon atoms, which group may be subsututed, or a group 20 o 01 0 o where n' is 1 to 6 and Y and Z are as already defined.

3 A material according to claim I or 2 wherein the cationic portion of the precursor (d) is an isothiuronium moiety of the formula:

2 i S R @W-s () H(It) 25 wherein m is 2 to 6, m' is 1 or 2, each of R' and R 2 is hydrogen or an alkyl group or R, and R 2 together are the atoms which complete a 5 or 6-membered hereocyclic nucleus, and R 3 is CHCONH or CHNHCONH when m' is 1 or, when m' is 2, is -NHCONH-, O:S= or C Hs SO 2 N=.

4 A material according to claim 1 or 2 wherein the cationic portion of the 30 precursor (d) is of the formula:

0 @> NH R 4 (m 1) H _p wherein p is 1 or 2, and R 4 is hydrogen or alkyl when p is 1 and, when p is 2, is alkylene.

1,590,190 A material according to claim 1 or 2 wherein the cationic portion of the precursor (d) is of the formula:

F 07 NA(CH 2)j(IV) wherein q is 1 to 6, r is 1 or 2, each of R 6 and R 7 is a hydrogen atom or an alkyi group, and R when r is 1 is

5 HN / N\ / and, when r is 2, is -NHCONH-, CH 3 SON=, -NHCO(CH 2)s CONH or -NHW-G CONHwhere S is 1 to 6.

6 A material according to claim 2 or claim 2 and any of claims 3 to 5 wherein 10 the cationic base portion of the precursor (d) has a p Ka value within the range 8 to 12 and the anionic portion thereof undergoes less than 10 % weight loss, except loss due to water release, in a thermogravimetric scan between 30 and 180 C where the scan rate is 40 C per minute.

7 A material according to claim 1 wherein the precursor (d) is a -neutral corn 15 pound comprising a cationic base portion derived from any of the Compounds A, D, E and F, and an anionic acid portion derived from any of the Compounds B, C, and G to L, specified herein.

8 A material according to any of the preceding claims which contains from 0 2 to 4 0 moles of the precursor (d) per mole of total silver 20

9 A material according to any of the preceding claims wherein the photographic silver salt (a) is a photographic silver halide.

A material according to any of the preceding claims wherein the developing agent (b) is a 3-pyrazolidone.

11 A material according to claim 1 substantially as described in any of the 25 Examples herein.

12 A coating composition for use in preparing a heat-developable sensitive photographic material as claimed in any of the preceding claims in which the constituents (a) to (d) are incorporated in a single layer, the composition comprising a dispersion of the specified constituents in a liquid 30

13 A method of making a heat-developable sensitive photographic material which comprises coating a support with a layer of a coating composition according to claim 12 and drying the layer.

14 A heat-developable sensitive photographic material made by a method according to claim 13 35 A method of making a photographic record which comprises exposing a sensitive photographic material as claimed in any of claims 1 to 11 and 14 to radiation to form a latent image therein and heating the material overall to develop the latent image to a visible image.

L A TRANGMAR, B Sc, C P A, Agent for the Applicants.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1981.

Published by the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.

1,590,190